JP5272910B2 - Construction machine fuel discriminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely discriminate the appropriateness of supplied fuel without a troublesome operation such as the operation of storing in advance a relation of temperature/density of the fuel. <P>SOLUTION: The elapsed time from the previous engine stop to the engine start this time is measured on the basis of an on/off signal of an engine switch 2. When the elapsed time is longer than a preset reference time, it is assumed that the fuel is supplied in the meantime and that the temperature of the fuel is stabilized to the room temperature. The appropriateness of the fuel is discriminated on the basis of the fuel density detected by a sensor 3. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fuel discriminating apparatus that discriminates whether or not fuel supplied to an engine is appropriate in a construction machine such as a hydraulic excavator.

  In general construction machines such as hydraulic excavators equipped with a diesel engine as a power source, light oil is appropriate as the fuel supplied to the engine, but unsuitable fuel such as kerosene is used. May be.

  When this unsuitable fuel is used, problems such as engine failure and generation of defective exhaust gas occur. Therefore, conventionally, a fuel determination device for determining the suitability of fuel has been proposed.

  For example, in Patent Document 1, the fuel density is detected every time an engine switch (so-called key switch) is turned on, and the appropriateness of the fuel is determined by comparing the detected fuel density with the density of the appropriate fuel (normal density). A technique for discriminating is disclosed.

  Patent Document 2 discloses a technique for detecting the fuel level in the fuel tank when the engine switch is turned on, and determining whether the fuel is replenished when the fuel level is above a certain level.

JP 2008-261811 A JP 2008-261759 A

  As in the prior art 1 described in Patent Document 1, in the method of determining the propriety of the fuel only on the condition that the engine switch is turned on without determining whether or not the fuel has been replenished, in particular, from the engine switch off. When the time to turn on is short, the fuel density is detected and discriminated in a state where the fuel temperature is still high (not returned to normal temperature for proper fuel).

  In this case, since the fuel density depends on the temperature, it is difficult to accurately determine whether or not the fuel density is appropriate.

  In the technique described in Patent Document 1, in order to cover this point, the relationship between the temperature of the fuel and the normal density is stored in advance in the control means, and the normal value obtained from the fuel temperature when the engine switch is turned on is stored. The density is compared with the detected actual density.

  However, since the fuel temperature changes under the influence of the engine temperature and the ambient temperature of the fuselage, it is necessary to make a fine correction according to these temperature changes, and the responsiveness of the discrimination execution including the responsiveness of the temperature sensor However, since there is a possibility that the temperature change cannot be accurately followed, there is a difficulty in the reliability of the suitability determination.

  Further, all the temperature / density characteristics of the fuel must be examined and stored in advance, and there is a problem that the setting work for this point is troublesome.

  On the other hand, according to the prior art 2 described in Patent Document 2, it is theoretically possible to determine whether or not fuel has been replenished by detecting the fuel level, and to determine the suitability of the replenished fuel.

  However, in reality, there is a possibility that the level sensor cannot detect a small level change. For this reason, if a replenishment method is employed in which fuel is replenished little by little and a certain level is maintained, replenishment determination cannot be made.

  Further, in the case of using an arm type level sensor, a change in fuel level outside the movable range of the arm cannot be detected.

  For this reason, according to the prior art 2, there is a risk that it may not be possible to determine whether the fuel is appropriate.

  Therefore, the present invention provides a fuel discrimination device for a construction machine that can easily determine the propriety of the replenished fuel easily and without the troublesome setting work such as storing the temperature / density relationship of the fuel in advance. Is to provide.

According to the first aspect of the present invention, an engine switch for operating start / stop of the engine, a sensor for detecting a physical quantity such as density of fuel supplied to the engine, and a fuel based on the physical quantity of fuel detected by the sensor. Control means for performing a discriminating action for determining the suitability of the engine, and this control means measures the elapsed time from the previous engine stop to the current engine start based on the on / off signal of the engine switch, and measures The discriminating operation is executed when the elapsed time is longer than a preset reference time , and the reference time is required for the fuel temperature to stabilize at room temperature during the time required for refueling. It was set taking time into account .

Here, the reference time may be set uniformly by the machine type may be set for each machine, or on a per-user basis.

  According to a second aspect of the present invention, there is provided a fuel temperature sensor for detecting a temperature of fuel supplied to the engine in the configuration of the first aspect, wherein the control means has a fuel temperature detected by the fuel temperature sensor as a fuel temperature. The above discriminating action is executed under the AND condition that the temperature is set in advance with reference to the normal temperature.

  According to the present invention, when the elapsed time from the previous engine stop to the current engine start is longer than the reference time, the fuel is replenished during that time, and the fuel temperature is stabilized at the normal temperature. Therefore, the suitability can be easily determined without the troublesome setting work such as investigating and storing the temperature / density relationship of the fuel in advance as in the technique described in Patent Document 1. A determination can be made.

Moreover,
(B) Since refueling is performed while the engine is stopped to ensure safety, there is no risk of missing fuel replenishment (without losing the timing of propriety judgment), provided that the reference time elapses.
(B) Since it is only necessary to determine suitability based on the detected physical quantity of the fuel, there is no need for correction according to the temperature change of the fuel as in the prior art 1 described in Patent Document 1, and the temperature Since there is no possibility of erroneous determination due to a response delay in detection and determination with respect to change, and there is no problem of erroneous detection of the fuel level as in the known technique 2, reliability of the suitability determination becomes high.

  By the way, the temperature of the fuel to be replenished is normally normal temperature, and the temperature of the whole fuel after replenishment approaches normal temperature as time passes.

  Accordingly, the fuel temperature is detected by the temperature sensor as in the second aspect of the invention, and the discriminating action is executed based on the AND condition that the detected fuel temperature is in a temperature range set in advance with the normal temperature of the fuel as a reference. By adopting the configuration, it is possible to more accurately grasp that the fuel has been replenished, that is, the timing for determining whether or not it is appropriate, and it is possible to determine whether or not it is necessary when necessary.

  In this case, it is only necessary to look at whether or not the fuel temperature is within the set range, and the reference temperature range may be the normal temperature of the fuel and a narrow range in the vicinity thereof, and the setting may be simple. Unlike the case of storing a wide range of temperature / density relationships as in (1), the setting operation is simple and there is no misjudgment factor such as correction.

1 is a system configuration diagram of a fuel discrimination device according to a first embodiment of the present invention. It is a block diagram which shows the content of the controller in FIG. It is a flowchart for demonstrating the effect | action of the apparatus. It is a system block diagram of the fuel discrimination | determination apparatus concerning 2nd Embodiment of this invention. It is a flowchart for demonstrating the effect | action of the apparatus.

1st Embodiment (refer FIGS. 1-3)
FIG. 1 shows a system configuration of the fuel discrimination device according to the first embodiment.

  This fuel discriminating apparatus includes a controller 1 as a control means, and an on / off signal of an engine switch (key switch) 2 and a physical quantity of fuel (depending on the type of oil. For example, density; hereinafter described in this example) A fuel density signal from the sensor 3 that detects the above is input to the controller 1.

  The on / off signal of the engine switch 2 may be an operation signal for starting the engine or an operation signal for turning on / off the power.

  As shown in FIG. 2, the controller 1 includes a timer 4, a storage / arithmetic processing unit 5, and an output unit 6.

  The timer 4 measures the elapsed time from the previous engine stop to the current engine start from the on / off signal of the engine switch 2 and sends the measured elapsed time to the storage / arithmetic processing unit 5.

  The storage / arithmetic processing unit 5 compares the elapsed time Tp with a preset reference time Ts, and determines whether the fuel is appropriate based on the fuel density detected by the sensor 3 when Tp> Ts.

  More specifically, the storage / arithmetic processing unit 5 stores in advance a normal density (a density range including a certain variation) of the appropriate fuel of the machine, and compares the detected fuel density with this normal density. Determine fuel adequacy.

  In addition, the reference time is determined based on the time required for fuel replenishment after the engine stops (tank capacity, replenishment method, etc., for example, 10 minutes), and the entire fuel including the replenished fuel is stabilized at the normal temperature. It is determined in consideration of the time required for (for example, 5 minutes).

  An ECU (engine control unit) 7, an indicator 8, a buzzer 9, and a communication device 10 are connected to the controller 1, and when it is determined that the replenished fuel is not regular fuel, the output unit 6 sends the engine 7 to the ECU 7. A stop command, a warning display command on the display 8, and an operation command on the buzzer 9 are output.

  As a result, the engine 11 is forcibly stopped, and a fuel improper display and a warning due to a buzzer operation are issued to the operator. At the same time, the communication device 10 notifies the management center 12 to that effect.

  The operation of this point will be described together with the flowchart of FIG.

  After the control is started by the engine switch-on operation, the elapsed time Tp from the previous engine switch-off to the current engine switch-on is calculated in step S1.

  In step S2, the elapsed time Tp is compared with the reference time Ts, and if it is determined that TP> Ts (longer than the reference time), the fuel density is detected in step S3.

  In step S4, the detected fuel density is compared with the normal density, and if it is within the normal range, the control is terminated. If it is out of the normal range (inappropriate), the buzzer is activated, the engine is stopped and managed in steps S5 to S7. Notification to the center 12 is performed.

  In this way, when the elapsed time from the previous engine stop to the current engine start is longer than the reference time, the fuel is replenished and the fuel temperature is stabilized at the normal temperature, and the suitability determination based on the fuel density is made. Therefore, it is possible to easily determine the suitability without a troublesome work such as investigating and storing the temperature / density relationship of the fuel in advance as in the technique described in Patent Document 1.

Moreover,
(B) Since refueling is performed while the engine is stopped to ensure safety, there is no risk of missing fuel replenishment (without losing the timing of propriety judgment), provided that the reference time elapses.
(B) Since it is only necessary to determine suitability based on the detected fuel density, there is no need for correction according to the temperature change of the fuel as in the prior art 1 described in Patent Document 1, and the temperature change There is no risk of erroneous determination due to a delay in response to detection and determination with respect to the above, and there is no problem of erroneous detection of the fuel level as in the prior art 2, so that the reliability of the suitability determination is high.

  In addition, when it is determined that the fuel is improper, it is positively displayed on the display 8 and the buzzer 9 is sounded, so that the user can clearly recognize that the improper fuel has been replenished.

  Further, the engine 11 is forcibly stopped to restrict the movement of the machine, and more forcible fuel management is possible. By notifying the management center 12, the fuel used by a third party can be monitored and recorded. .

Second embodiment (see FIGS. 4 and 5)
Only differences from the first embodiment will be described.

  In the second embodiment, a fuel temperature sensor 13 for detecting the fuel temperature is provided, and a configuration for determining whether or not the fuel is appropriate based on an AND condition that the detected fuel temperature is within a set range is adopted.

  The operation will be described with reference to the flowchart of FIG.

  After the elapsed time Tp is calculated and compared with the reference time Ts in steps S11 and S12 (corresponding to steps S1 and S in FIG. 3), the temperature and density of the fuel are detected in step S13, and the fuel is detected in step S14. It is determined whether or not the temperature is within a set range.

  The set range refers to a certain range including variation in normal fuel normal temperature. If the set range is within the set range, it is determined that the fuel is a normal fuel, and the process proceeds to step S15. .

  Subsequent steps S16 to S18 are the same as steps S5 to S7 in FIG. 3, and a buzzer operation, engine stop, and management center notification are performed, respectively.

  According to the second embodiment, by checking the fuel temperature, it is possible to more accurately grasp that the fuel has been replenished, that is, the timing for determining whether or not it is appropriate, and execute the appropriateness determination required when necessary. it can.

  In this case, it is only necessary to look at whether or not the fuel temperature is within the set range, and the reference temperature range may be the normal temperature of the fuel and a narrow range in the vicinity thereof, and the setting may be simple. Unlike the case of storing a wide range of temperature / density relationships as in (1), the setting operation is simple and there is no misjudgment factor such as correction.

  By the way, as a measure to limit the movement of the machine when it is determined that the fuel is inappropriate, a hydraulic lock that stops the hydraulic operation of the machine may be applied instead of stopping the engine, or the engine speed Alternatively, the discharge flow rate of the hydraulic pump may be limited.

  Alternatively, no such restriction may be added.

  In addition, after refueling, the time until the temperature of the whole fuel stabilizes at the normal temperature varies within a certain range depending on the replenishment amount and the ambient temperature. It is not always necessary to set the fuel temperature as a condition for determining suitability.

  On the other hand, a physical quantity (kinematic viscosity, capacitance, etc.) having different characteristics depending on the fuel other than the density of the fuel may be detected by a sensor.

DESCRIPTION OF SYMBOLS 1 Controller as control means 2 Engine switch 3 Sensor 4 Timer which measures elapsed time 5 Memory | storage / arithmetic processing part 6 Output part 11 Engine 13 Fuel temperature sensor

Claims (2)

An engine switch for operating start / stop of the engine, a sensor for detecting a physical quantity such as a density of fuel supplied to the engine, and a discriminating function for judging the suitability of the fuel based on the physical quantity of the fuel detected by the sensor The control means measures the elapsed time from the previous engine stop to the current engine start based on the on / off signal of the engine switch, and the measured elapsed time is The discriminating action is executed when the time is longer than a set reference time , and the reference time is set by adding the time required for fuel temperature to stabilize at room temperature in addition to the time required for refueling. A fuel discrimination device for construction machinery.   A fuel temperature sensor for detecting a temperature of the fuel supplied to the engine, wherein the control means has a fuel temperature detected by the fuel temperature sensor in a temperature range set in advance with reference to a normal temperature of the fuel; 2. The fuel discriminating apparatus for a construction machine according to claim 1, wherein the discriminating action is executed under the AND condition.

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